Renewable energy systems (e.g., a wind farm) are often located in remote areas to take advantage of uninterrupted weather systems, for example, no buildings or other structures impeding wind flow, as well as being located to minimize negative viewpoints/attitudes akin to ‘not in my backyard’. Similarly systems monitoring the electromagnetic spectrum (e.g., a radar-based system) are also often located in remote, sparsely populated regions.
Further, with regard to a wind-based energy system, higher placement of the turbine blades above the earth's surface can lead to enhanced capturing of wind energy as turbulent effects of the wind flowing over the earth's surface (e.g., over the landscape, over trees, etc.) are reduced. Hence, a turbine nacelle and wind turbine blades are oftentimes located on a tall supporting structure to facilitate placement of the turbine blades in airflow having reduced turbulence.
Unfortunately, location of a system utilizing electromagnetic radiation proximate to a wind turbine can result in disruption of the electromagnetic radiation signaling. For example, as shown in FIG. 11, a radar station 1100 is co-located with one or more wind turbines 1120, where each wind turbine 1120 can comprise a blade(s) 1130, a nacelle 1140, and a support tower 1150. Radar system 1100 is transmitting electromagnetic waves 1110 to facilitate detection of moving objects, such as an aircraft 1170. However, motion of blade(s) 1130 can engender a Doppler effect in reflected waves 1160, which are generated by reflection of the electromagnetic waves 1110 by blade(s) 1130. Reflected waves 1160 can be of varying frequency (e.g., wavelengths x and y) based on the frequency of rotation of blade(s) 1130 accompanied by continual re-orientation of blade(s) 1130 to the wind direction. Essentially, the Doppler effect is created by motion of blade(s) 1130 towards radar system 1100 and motion away from radar system 1100. Owing to such Doppler effect, it can be difficult for radar system 1100 to accurately differentiate between a static object and a moving object. Similarly, a Doppler-based system that monitors weather may erroneously determine a weather system based on Doppler effect being generated by one or more wind turbines (e.g., the one or more wind turbines 1120) in a wind farm.
To overcome such deleterious effects, it is possible to upgrade the sensing/operational logic of a radar system to facilitate improved determination of object motion, however such system upgrade can be costly, impractical, etc. Alternatively, the profile/cross-section of a turbine blade(s) can be modified to minimize its effective radar cross-section (RCS), however, such modification is limited by the profile required to capture the wind flowing over the blade surface to generate wind energy. Further, the ability to modify components comprising a turbine blade are somewhat limited by how amenable an existing fabrication technique utilized in the manufacture of a turbine is with regard to incorporation of new or modified materials. For example, ability to incorporate a novel material into a turbine blade using conventional fiber lay-up techniques such as wet-layup, resin transfer molding (RTM), vacuum assisted resin transfer molding (VARTM), pre-impregnated (pre-preg), etc.
Hence, while approaches are available to minimize deleterious effects resulting from co-location of systems utilizing electromagnetic radiation signaling and renewable energy systems, such approaches can be limited in their effectiveness in reducing radar signature.